Former U.S. Vice President Al Gore may have inadvertently spilled some secrets about Apple Inc.’s (Nasdaq: AAPL) upcoming release of the next-generation of SmartPhones by declaring at a scientific forum of "new iPhones coming next month."

As a board-member at Apple, Gore may indeed be privy to inside corporate knowledge; however, such a slip of the tongue would likely never be perpetrated by a chief executive.

Then, one has to wonder why Gore was elected to the board of the world’s largest technological company in the first place? Moreover, broadly speaking, why are “celebrities” placed on boards of companies -- often in industries where they would appear to have no tangible connection to?

Indeed, many celebrities, including politicians, actors, musicians and even athletes have been named to corporate boards over the decades.

However, it is unclear what long-term value, if any, they provide to the companies’ underlying stock prices.

Generally speaking, celebrity directors endow companies with sudden prominence, name recognition, some glamour, and, in many cases, a short-term spike in the stock price.

Anna N. Danielova, assistant professor of finance at DeGroote School of Business in Hamilton, Canada, explained to International Business Times that corporations sometimes put celebrities on their boards because it provides an opportunity for the company to increase its visibility and exposure through the fame, reputation, and status associated with a celebrity director on board.

“In addition, a celebrity could bring in important networking connections, or shift investors’ perceptions of a firm into a more positive direction,” she said. “This could lead to value-creation. And in fact, it [often] does.”

Danielova cited a preliminary study that examined nearly 800 celebrity appointments to corporate boards from 1985 to 2006.

“The boards that included celebrities enhanced shareholders value over one-, two- and three-year horizons,” she said. “In addition, the announcement of celebrity appointments to corporate boards produced an immediate positive market response.”

It would be impossible to list all the celebrities who have held seats on U.S. corporate boards; however, it’s safe to say a great many of them (like Gore) have come from the realm of politics and national government.

Such a “marriage” between lawmakers and big business would seem to be a natural fit – although often raising the potential for conflicts of interest.

For example, Donald Rumsfeld, the former Secretary of Defense, enjoyed a long tenure as director at Swiss-based European engineering conglomerate ABB Ltd. (NYSE: ABB) -- a company that once sold two light-water nuclear reactors for installation in Communist North Korea,

Former Secretary of State Condoleezza Rice has served on the boards of Chevron Corp. (NYSE: CVX), Charles Schwab Corp. (NYSE: SCHW) and Hewlett Packard (NYSE: HPQ), among many others.

Former U.S. Secretary of Defense and ex-CIA director Robert Gates once served on the board of SAIC Inc. (NYSE: SAI), which receives many government defense contracts – again, creating the potential for conflicts of interest.

Andrew Young, the former Mayor of Atlanta, Congressman from Georgia and U.S. Ambassador to the United Nations, was once on the board of agricultural behemoth Archer-Daniels Midland Co. (NYSE: ADM). In 1999, Young caused outrage when, after ADM pled guilty to charges of price-fixing, he claimed the company was not “driven by greed.”

Perhaps former Democratic Governor and Indiana Senator Evan Bayh and his wife Susan are in a class by themselves as far corporate involvement by politicians is concerned.

In June of this year, Evan Bayh joined the board of Cincinnati-based bank, Fifth Third Bancorp (Nasdaq: FITB).

Meanwhile, Susan Bayh has raked in millions sitting on the boards of Indianapolis-based health insurer WellPoint Inc. (NYSE: WLP), as well as at fourteen other companies since 1994 (while her husband held high political office).

The Indiana Journal Gazette has described her as a "professional board member.”

Regarding the potential for conflicts of interest arising from Susan’s many directorships and Evan’s political office, he told an Indiana newspaper in 2007: “I can honestly tell you that if my wife did not have a job, none, I can't think of a single decision I've made that would be any different. I look at what's best for our state and our country and my own conscience. My integrity matters more to me than anything, so I always do what's right for the people who put their trust in me.”

Again defending his wife and himself, Evan once told the Journal Gazette: “I don’t even know the people who run the vast majority of her companies. I’ve never even spoken to them. The reality is, we don’t talk about stuff that she’s involved with.”

However, many non-politicians have also found themselves in the ranks of company directors – some of which may appear to be bizarre on the surface.

Spiritualist and author Deepak Chopra is a board member of clothing retailer Men's Wearhouse (NYSE: MW).

Consider the case of lady golfer Nancy Lopez-Knight.

In May 2006, J. M. Smucker Co. (NYSE: SJM), the food manufacturer perhaps best known for its jelly product, nominated Lopez-Knight to its board. She officially became an independent director of the company in August of that year.

While it would be difficult to find any direct connection between golf and jam, it is interesting to note that Smucker shares have about doubled since Lopez-Knight joined the board.

Basketball legend Julius ‘Dr. J’ Erving has served on the boards of Saks Inc. (NYSE: SKS), Fusion Telecommunications, WilTel Communications Group and Darden Restaurants (NYSE: DRI).

Pro football Hall of Famer Lynn Swann has served on the boards of such diverse firms as H.J. Heinz (NYSE: HNZ), private gaming corporation Caesars Entertainment and Transdel Pharmaceuticals.

Wayne Rogers, a former actor probably best known for appearing on the popular 1970s television comedy series MASH, is on the board of directors of semiconductor manufacturer Vishay Intertechnology Inc. (NYSE: VSH).

As far as Al Gore is concerned, he has had a peculiar term at Apple, having joined the board in March 2003.

Of course, his term as director has coincided with Apple’s extraordinary success, due to the immense popularity of an array of devices, including the iPhone and iPad. But it is doubtful that Gore can take much credit for the company’s stellar performance.

At the time of Gore’s election to the board, then-chief executive Steve Jobs gushed in a statement: “Al brings an incredible wealth of knowledge and wisdom to Apple from having helped run the largest organization in the world -- the United States government -- as a Congressman, Senator and our 45th Vice President… Al is going to be a terrific director and we’re excited and honored that he has chosen Apple as his first private sector board to serve on.”

Large words indeed… but what has Gore actually contributed to Apple?

Indeed, this past February, Gore was mocked by shareholders during a meeting at company headquarters in Cupertino, Cal.
According to CNET, one longtime stockholder sneered: "[Gore] has become a laughing-stock. The glaciers have not melted. If [the] advice he gives to Apple is as faulty as his views on the environment then he doesn't need to be re-elected"

However, Danielova sees value in Gore’s presence at Apple.

“Al Gore is not only a celebrity, he is a politician,” she noted.

“And having someone with political connections on board could be very, very valuable.”

She cited a 2006 study which showed that a company experiences a positive and statistically significant abnormal stock return of almost 1 percent following the announcement of a board nomination of a politically-connected individual.

“This positive announcement-effect holds true both for Republican and Democrat directors,” she said.

“By comparison, independent non-political directors do not generate a positive abnormal return.”

However, Danielova concedes it would be difficult to quantify Gore’s impact on Apple.

“He could have helped thorough his political connections, he could have brought even more awareness to Apple around the globe, with his environmentalism movement and in particular, his successful movie ‘An Inconvenient Truth’,” she added.

However, since the onset of the global economic crisis and recession, celebrity directorships may be on the wane – although there is no hard evidence to back this assertion.

“Since 2009, after the financial meltdown, there [has been] an increase in disclosure requirements regarding the qualifications of directors,” Danielova noted.

Presumably, if a celebrity director is desired only to add ‘glamour’ and ‘buzz’ to a company, the SEC may not look too kindly upon such an appointment.